An X-ray CT apparatus is an apparatus that scans a subject using X-rays, and processes thus collected data by a computer, to image internal parts of the subject.
Specifically, the X-ray CT apparatus applies X-rays from various directions to a subject several times, and detects X-ray signals that have passed through the subject with an X-ray detector. This X-ray detector is a multi-row detector that has multiple X-ray detection devices in a channel direction (rotation direction) and a slice direction (body axis direction). The X-ray CT apparatus collect detected signals, and performs preprocessing and the like after analog/digital (A/D) conversion, to generate projection data. The X-ray CT apparatus then performs reconstruction processing based on the projection data, to generate images.